Answer:
If they would have abolished slavery in 1860 or 1861 the South would have seceded faster which that's not that much of a change. Also if they abolish slavery and then lose the war that would look bad if it wasn't a huge catastrophe.
Step-by-step explanation:
So, I think what they did was smart and right. If they did it to early it could have backfired and towards the end of the war the Union was obviously the victor.